Header for print stylesheet
You are here:    

Vitamin C and nursery pigs

The old school of nutrition holds that vitamin C supplementation is unnecessary in swine. Pigs begin to synthesize the vitamin within a week after birth, and before then, their dams' milk provides a rich source of ascorbic acid. Now, however, research suggests that dietary supplemental vitamin C can play a valuable role in swine nutrition during the first weeks after weaning. It may be especially appropriate in operations that practice segregated early weaning (SEW).

Behind the current interest in vitamin C supplementation following weaning are several concerns. First, pigs do not develop complete synthesizing capacity until about eight weeks of age, or five to six weeks after they're weaned in modern production systems. Also, feedstuffs used in rations do not replace the vitamin C in sows' milk because they contain little if any ascorbic acid.

Further, modern production techniques have increased the animals' need for ascorbic acid through environmental stresses and continual demand for higher productivity. Kolb (1984) summarized various types of stress that increase animals' requirements for vitamin C while reducing their ability to synthesize it. These included deficiencies in various dietary components (energy content, protein, vitamin E, selenium, iron); production or performance stress; transportation, animal handling and new environmental location stress; temperature; and disease and parasites. Scientists have also suggested that the intensive genetic selection that has taken place in the swine industry may have altered the enzymatic constitution of animals and their ability to synthesize vitamin C.

Mahan and Saif (1983) showed a decline in plasma ascorbic acid during the initial period postweaning, suggesting inadequate synthesis of the vitamin. Wegger and Palludan (1984) reported that early weaning tended to decrease levels of vitamin C in pigs' livers.

Now, four studies have found improved performance in newly weaned pigs receiving dietary vitamin C supplementation compared to unsupplemented controls. For example, a 1993 study (Mahan) at The Ohio State University compared live performance of 288 pigs receiving 0, 50 or 500 ppm vitamin C. Weaning occurred at 23 days of age, and the pigs were evaluated for 35 days. Pigs receiving either level of dietary vitamin C supplementation grew significantly faster (P < 0.05), with improved feed conversion (P < 0.10), than the controls during the first 14 days postweaning (Table 1).
Table 1

A study at Oklahoma State University compared supplementation at 0, 75 and 150 ppm with either SEW at 14 days or conventional weaning at 20 days. The 72 pigs in the SEW group were studied for 42 days, and the 120 pigs in the conventionally weaned group for 30 days postweaning.

For the SEW pigs, average daily gain and feed efficiency were significantly improved compared to unsupplemented controls during Phase 1 (days 0-14) and Phase 3 (days 28-42) and for the entire period (Table 2). At 9.4 percent during the first phase, the increase in gains was greatest at 75 ppm. The 120 conventionally weaned pigs (20 days) also had improved average daily gain and feed efficiency during the first 17 days after weaning with vitamin C in the diet.
Table 2

"These results suggest an inadequate dietary vitamin C level during the first 42 days postweaning in pigs weaned as early as 12 days of age and reared in an off-site nursery facility and during the first 17 days postweaning in pigs weaned at 20 days of age and kept in a conventional nursery system," says Dr. Brenda de Rodas, one of the researchers participating in the study. "A supplemental level of 75 ppm was adequate to meet the dietary vitamin C requirement of the early-weaned pig. Vitamin C supplementation will improve performance in young pigs during the high-stress postweaning period and may be particularly beneficial to pigs weaned at a very early age."

A study at the Agricultural University of Athens also showed significantly improved live performance in supplemented pigs (120 ppm vitamin C) compared to unsupplemented controls. Both groups of 100 pigs were weaned at 25 days and then studied for five weeks. Average daily gain was statistically greater for weeks two (22.2 percent) and three (15.1 percent) in supplemented pigs. Live weights were also statistically greater in supplemented pigs for weeks one through four postweaning (15.6, 17.0, 15.3 and 13.4 percent, respectively). There was a numerical 8 percent difference in week five. In this study, feed consumption was greater in supplemented pigs but feed conversion did not improve--in contrast to the studies conducted in the U.S.

Currently, researchers at Ohio State are conducting another study of postweaning vitamin C supplementation. Preliminary results seem to agree with those at Oklahoma State, says Dr. Donald Mahan. "We see a significant difference between the zero and 75 ppm levels. Then the response seems to plateau."

Because vitamin C is readily oxidized when exposed to oxidizing agents such as oxygen and minerals, a chemically stabilized form was used in all four studies. In Stay-C®, vitamin C is protected from oxidation during processing and storage of premixes and feeds by attaching phosphate groups to the ascorbic acid molecules. After the feed is consumed, phosphatases in the intestine release the vitamin C for absorption and distribution to the tissues.

Based on these studies, it appears supplementation with stabilized vitamin C is related to improved performance during the first several weeks postweaning. Further research is needed to determine optimal levels from both a performance and economic standpoint.

References:

  • Cafantaris, B. 1996. Vitamin Stay C-25 in pigs. Agricultural University of Athens (report).
  • De Rodas, B.Z., et al. 1997. Efficacy of Rovimix Stay-C as a vitamin C source for weanling pigs. J. Anim. Sci. abstract.
  • Kolb, E. 1984. Metabolism of ascorbic acid in livestock under pathological conditions. Proc. workshop on ascorbic acid in domestic animals. Royal Danish Agri. Soc.
  • Mahan, D.C. 1993. Supplemental vitamin C for swine--is it essential and if so when are the critical stages? Ohio Swine Research and Industry Report, Animal Science Series 92-2, pp. 60-65.
  • Mahan, D.C., and L.J. Saif. 1983. Efficacy of vitamin C supplementation for weaning swine. J. Anim. Sci. 56:631.
  • Wegger, I., and B. Palludan. 1984. Ascorbic acid status in swine. Proc. workshop on ascorbic acid in domestic animals. Royal Danish Agri. Soc.

 
Vitamin C

Is required for the formation of collagen, the intracellular substance that gives structure to muscles, vascular tissues, bones and cartilage. It is also considered one of the most important antioxidant vitamins in intracellular and extracellular fluids.

 
Related topics
footer for print stylesheet